This invention relates to a shake detecting and correcting device and a shake detecting and correcting method for an optical apparatus, such as camera.
Recently, there have been proposed various cameras capable of shake correction. One such camera is of an image processing type in which an area sensor comprising a multitude of photoelectric conversion elements such as Charge Coupled Devices (CCDs) arrayed in a two-dimensional form is used to detect a shake amount of an object light image particularly resulting from a camera shake, and a displacement of the object light image is corrected in such a manner as to cancel the shake amount (Japanese unexamined Patent Publication No. HEI 8-51566).
More specifically, an instant object image is extracted during a sensing operation by the area sensor, and the extracted object image is compared with a base image to detect a shake amount. An estimative shake amount is calculated based on plural shake amounts to move a shake correction lens in such a direction as to cancel the shake amount.
In the case where a shake amount is detected according to the image processing system using an area sensor such as CCD, a received light amount on each photoelectric conversion elements of the area sensor varies as the luminance of an object light image changes due to a change of a photographic condition and the like. Accordingly, a luminance variation is involved in the picked up object light image. If a shake detection is performed based on picked up image data including a luminance variation, an estimative shake amount will be affected by the luminance variation, thereby making it impossible to perform a proper shake correction.